Gigabit Linux Routers

David Coulson david at
Wed Dec 17 14:21:23 UTC 2008

I've been pretty happy running IBM x-series hardware using RHEL4. 
Usually it's PPS rather than throughput that will kill it, so if you're 
doing 250Mbit of DNS/I-mix/HTTP, you'll probably have very different 
results. There are some rx-ring tweaks for the NICs that are needed, but 
on the most part it's all out of the box (No custom kernel patches, and 
such - Just some sysctl settings).

I have two x3650s (Quad core) doing around 6-700Mbit/sec (40k pps) at 
around 20% CPU right now. No Quagga BGP, but that's minimal in terms of 
CPU. I've not been able to get much beyond 1Gb/sec on this environment 
because my ASAs are not configured to support more than one Gig into 
that particular network.

Chris wrote:
> Hi All,
> Sorry if this is a repeat topic. I've done a fair bit of trawling but can't
> find anything concrete to base decisions on.
> I'm hoping someone can offer some advice on suitable hardware and kernel
> tweaks for using Linux as a router running bgpd via Quagga. We do this at
> the moment and our box manages under the 100Mbps level very effectively.
> Over the next year however we expect to push about 250Mbps outbound traffic
> with very little inbound (50Mbps simultaneously) and I'm seeing differing
> suggestions of what to do in order to move up to the 1Gbps level.
> It seems even a dual core box with expensive NICs and some kernel tweaks
> will accomplish this but we can't afford to get the hardware purchases
> wrong. We'd be looking to buy one live and one standby box within the next
> month or so. They will only run Quagga primarily with 'tc' for shaping.
> We're in the UK if it makes any difference.
> Any help massively appreciated, ideally from those doing the same in
> production environments.
> Thanks,
> Chris

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